assembly optimization, pr nits

Uniswap · Aug 4, 2024 · 4a74d8d · 4a74d8d
1 parent e553340
commit 4a74d8d
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Showing 4 changed files with 15 additions and 7 deletions.
diff --git a/.forge-snapshots/PositionManager_permit.snap b/.forge-snapshots/PositionManager_permit.snap
@@ -1 +1 @@
-79636
+79566
diff --git a/.forge-snapshots/PositionManager_permit_secondPosition.snap b/.forge-snapshots/PositionManager_permit_secondPosition.snap
@@ -1 +1 @@
-62524
+62454
diff --git a/.forge-snapshots/PositionManager_permit_twice.snap b/.forge-snapshots/PositionManager_permit_twice.snap
@@ -1 +1 @@
-45412
+45342
diff --git a/src/base/EIP712.sol b/src/base/EIP712.sol
@@ -15,8 +15,8 @@ contract EIP712 is IEIP712 {
     uint256 private immutable _CACHED_CHAIN_ID;
     bytes32 private immutable _HASHED_NAME;
 
-    bytes32 private constant _TYPE_HASH =
-        keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");
+    /// @dev equal to keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)")
+    bytes32 private constant _TYPE_HASH = 0x8cad95687ba82c2ce50e74f7b754645e5117c3a5bec8151c0726d5857980a866;
 
     constructor(string memory name) {
         _HASHED_NAME = keccak256(bytes(name));
@@ -37,7 +37,15 @@ contract EIP712 is IEIP712 {
     }
 
     /// @notice Creates an EIP-712 typed data hash
-    function _hashTypedData(bytes32 dataHash) internal view returns (bytes32) {
-        return keccak256(abi.encodePacked("\x19\x01", DOMAIN_SEPARATOR(), dataHash));
+    function _hashTypedData(bytes32 dataHash) internal view returns (bytes32 digest) {
+        // equal to keccak256(abi.encodePacked("\x19\x01", DOMAIN_SEPARATOR(), dataHash));
+        bytes32 domainSeparator = DOMAIN_SEPARATOR();
+        assembly ("memory-safe") {
+            let fmp := mload(0x40)
+            mstore(fmp, hex"1901")
+            mstore(add(fmp, 0x02), domainSeparator)
+            mstore(add(fmp, 0x22), dataHash)
+            digest := keccak256(fmp, 0x42)
+        }
     }
 }